1. Field of the Invention
The present invention relates to methods and systems for remotely administering hearing tests, in which the subjects of the test use consumer electronic equipment coupled to communication media, such as Internet connected personal computers, cell phones, personal digital assistants, personal audio equipment, and the like, for the generation of stimuli during the test.
2. Description of Related Art
Hearing tests are used to develop hearing profiles of persons, which can be used for fitting hearing aids and for other diagnostic purposes. Professional audiologists are typically required for conducting the tests needed to provide a hearing profile, because of the large number of factors involved in making an assessment necessary for generating a reliable hearing profile. An audiologist is able to set up a controlled environment, and conduct the test according to a testing protocol involving a number of stimuli and response steps that is adapted based on the responses gathered during the test.
The hearing profiles of individuals vary in a number of ways. The ability to hear sounds varies with frequency among individuals across the normal audio frequency range. Also, the dynamic range varies among individuals so that levels of an audio stimulus that are perceived as soft sounds and levels of an audio stimulus that are perceived as loud sounds differ from person to person. Standard hearing tests are designed to produce an audiogram that characterizes such factors as frequency, sensitivity and dynamic range in the hearing profiles of individuals. There are also other factors that affect a hearing profile. For example, psycho-acoustic factors concerning the manner in which a person perceives combinations of normal sounds affect the ability to hear in ways that can vary from person to person. Also, environmental factors such as the usual listening environment of a person (library, conference room, concert hall) and the equipment on which the sound is produced (loud speakers, ear phones, telephone hand set) are important. In persons wearing hearing aids or using other assistive hearing devices, the type of aid or device affects the hearing profile. The physiology of an impairment suffered by the individual may also be an important factor in the hearing profile.
The hearing profiles of individuals have been applied in the hearing aid field for customizing and fitting hearing aids for individuals. See, for example, U.S. Pat. No. 4,731,850 entitled PROGRAMMABLE DIGITAL HEARING AID SYSTEM, invented by Levitt et al.; and U.S. Pat. No. 5,848,171 entitled HEARING AID DEVICE INCORPORATING SIGNAL PROCESSING TECHNIQUES, invented by Stockham, Jr. et al. Thus, techniques for processing sound to offset variations in hearing are well known. However, these techniques are unavailable to persons not using hearing aids. Furthermore, many persons who could benefit from such processing are not in position to use hearing aids for a variety of reasons.
A variety of uses for hearing profiles, other than for the purposes of prescribing hearing aids and assistive listening devices, is being developed. For example, hearing profiles of individuals can be utilized for producing customized audio products, such as pre-recorded music that has been modified according to the hearing profile of the listener. One medium for delivering customized audio products is the Internet. See, co-pending U.S. patent application Ser. No. 09/957,344, entitled SOUND ENHANCEMENT FOR MOBILE PHONES AND OTHER PRODUCTS PRODUCING PERSONALIZED AUDIO FOR USERS, invented by Rader, et al. filed 20 Sep. 2001; and co-pending U.S. patent application Ser. No. 09/464,036, entitled SYSTEM AND METHOD FOR PRODUCING AND STORING HEARING PROFILES AND CUSTOMIZED AUDIO DATA BASED ON SUCH HEARING PROFILES, invented by Pluvinage, et al., filed 15 Dec. 1999.
Because of the difficulty in obtaining a hearing assessment test, and for a variety of other reasons, many persons who could benefit from devices that would assist their hearing do not follow through with obtaining a prescription for such devices. Thus, it is desirable to simplify the procedures involved in obtaining a reliable hearing assessment.
U.S. Pat. No. 5,928,160 describes a home hearing test system and method based on the use of calibrated headphones specially manufactured to support the hearing test using home audio equipment. In addition, reference is made to this patent for its discussion of background concerning hearing assessment tests in general. However, home hearing assessment tests have not achieved commercial acceptance.
Some efforts have been made to develop a technique for allowing a web site visitor to measure their hearing loss in an efficient and consistent way that is self-administered. Some of these attempts have implemented procedures that are similar to if not identical to a clinical audiogram, where a tone is presented and the listener responds if they heard the sound, in a type of yes-no threshold test. Other attempts implement a screening procedure where tones are presented and results are based on whether or not you heard those tones with no adjustment of sound presentation based on user response.
The yes-no procedures of the prior art are not well suited for self-administered testing, and web implementation of a hearing test demands self-administration. One reason is because the listener can fake a threshold and pretend that they are better than they really are, and yes-no procedures are susceptible to user bias. The prior art tests that do not adaptively find a hearing threshold are crude screeners that do not provide significant information about the person's hearing loss. The prior art tests that adapt the stimulus based on user input, also use basic yes-no procedures. Thus the result is determined based on analysis of yes responses and no responses to a sequence of queries. See, e.g., ANSI S3.21-1978, “Methods for Manual Pure-Tone Threshold Audiometry,” and the description of computer controlled Bekesy Audiometry in ANSI S3.6-1996, “Specification for Audiometers.”
More sophisticated testing algorithms are known which use standardized psychological procedures which improve the reliability and repeatability of the hearing loss measure, but such algorithms have not been applied in uncontrolled environments, like the internet. See, Levitt H., “Transformed up-down methods in psychoacoustics,” J Acoust Soc Am. February 1971;49(2):Suppl 2:467+; Edwards B W, Wakefield G H. “Small sample statistical analysis of Levitt's adaptive psychophysical procedure,” J Acoust Soc Am 1988 Apr 85, S 1:121; Schlauch R S, Rose R M. “Two-, three-, and four-interval forced-choice staircase procedures: estimator bias and efficiency,” J Acoust Soc Am. August 1990;88(2):732-40; Green D., “A maximum-likelihood method for estimating thresholds in a yes-no task,” J Acoust Soc Am., April 1993, 93: 2096-2105; and Green D., “Maximum-likelihood procedures and the inattentive observer,” J Acoust Soc Am. June 1995;97(6):3749-60.
As the Internet gains popularity, and more individuals obtain the general-purpose processing power of personal computers coupled to the Internet and having sound cards or other audio processing capability, the Internet is becoming a more important medium for the delivery of audio products. Accordingly, it is desirable to leverage the communication technology the Internet used in the delivery of audio products for the purposes of performing hearing assessments in the home.